1. Field of the Invention
The present invention relates to an antiviral agent and a method of producing the same. In particular, the present invention relates to an antiviral agent of an excellent antiviral ability against various viruses without releasing any substance to damage health of animals and plants. The present invention also relates to a method of producing the same.
2. Description of the Related Art
As a sterilizing treatment, fish and shellfish are immersed in an aqueous solution containing sodium hypochlorite before being shipped to fish shops, department stores, supermarkets or the like. The fish is transported after being frozen. Further, the so-called shucked raw shellfish of scallop and oyster to be eaten is transported after it is accommodated in a container and is maintained at a temperature of 5 to 6xc2x0 C.
The sterilizing treatment and the transport at the low temperature prevent food poisoning by decreasing the number of bacteria. That is, the sterilizing treatment greatly reduces the number of bacteria including pathogenic Escherichia coli such as O-157, cell-invasive bacteria, Salmonella or the like. Further, a minute amount of the surviving bacteria does not propagate at the low temperature. Therefore, the number of bacteria can be kept small until the fish and the shellfish are eaten. In other words, since the number of bacteria such as O-157 and Salmonella does not increase at the low temperature, probability of the bacterial food poisoning is greatly low in winter.
However, it is often reported that one presents a symptom of the food poisoning although he or she eats in winter the sterilized seafood which has been transported at the low temperature. Recent studies elucidate that the above food poisoning is not a bacterial one but is a viral one which is caused by the virus including spherical small virus (hereinafter referred to as xe2x80x9cSRSVxe2x80x9d), astrovirus, rotavirus or the like.
In the viral food poisoning, the above viruses parasitic on the seafood invade a human body if he or she eats the seafood that is not heat-treated. Next, the viruses propagate while destroying mucosal cells of bowels or the like and, as a result, induce enterogastritis symptoms such as diarrhea, emesis, fever or the like. Actually, if the bacteria is not detected in the vomit and excreta of a person who presents the symptom of the food poisoning, the viruses are detected in many cases. Since SRSV is detected frequently in particular, it is supposed that almost all of the viral food poisoning may be caused by SRSV.
For preventing the viral food poisoning, it is assumed to use a substance which reduces the number of viruses and which inhibits the viral propagation for a long period of time. However, a method of cultivating SRSV has not been established yet and it is greatly difficult to investigate what kind of substance is able to be antiviral against SRSV. At present, sodium hypochlorite is used as a usual sterilant on the assumption that it may be effective to SRSV as well. However, as described above, the viral food poisoning is generated in some cases even if the seafood immersed in the aqueous sodium hypochlorite solution is eaten and even the sodium hypochlorite cannot completely prevent the viral food poisoning.
Further, liberated from sodium hypochlorite, chlorine sometimes adheres to the seafood that is sterilized with the aqueous sodium hypochlorite solution. The chlorine is well known as a toxic substance, and the mucous membrane of lungs, nostril or the like is damaged if the chlorine is ingested at a high concentration. Furthermore, there is a possibility that arteriosclerosis occurs due to constant and continuous ingestion of the chlorine whose concentration is even low. That is, it is not favorable for the health to eat the seafood adhered with the liberated chlorine.
Further, if the liberated chlorine is reacted with an organic matter remaining in tap water as a solvent, carcinogenic methane trihalide (trihalomethane) is generated and adheres to the seafood. It is not favorable for the health to eat the seafood adhered with the carcinogenic substance.
As understood from the above, there is a problem that it is not favorable for the human health to sterilize the seafood with the aqueous sodium hypochlorite solution.
It is an object of the present invention to provide an antiviral agent of an antiviral ability against various viruses and of a possible antiviral ability against SRSV as well without releasing any substance to damage health of animals and plants, and a method of producing the same. The xe2x80x9cantiviral abilityxe2x80x9d in the present invention is a term to indicate abilities to kill the virus and to prevent the virus from propagating.
Even a substance of an antiviral ability against a certain virus is not always able to be antiviral against SRSV. Therefore, it is necessary to determine whether or not the substance has the antiviral ability against SRSV by contacting the substance and SRSV with each other to perform a cultivation test.
However, a nature of SRSV has not been clarified yet. Although a method of detecting SRSV is established, methods of cultivating SRSV and of confirming life or death thereof have not been established. For this reason, it is greatly difficult to develop an agent of the antiviral ability against SRSV, i.e., the ability to greatly decrease the number of viruses of SRSV for a short period of time. That is, it is impossible to confirm efficacy of the medicine because it is impossible to confirm the life or the death of SRSV. Accordingly, National Institute of Health is of the opinion that a substance possibly has the antiviral ability against SRSV virus as well if it has the antiviral ability against herpes simplex virus type 1, adenovirus type 3, influenza virus type A, and coxsackie virus group B type 1 which are representative viruses in classification.
That is, as well known, the virus is roughly classified depending on whether the nucleic acid coated with capsid is deoxyribonucleic acid (DNA) or ribonucleic acid (RNA). The virus is finely classified depending on whether or not it possesses envelope for coating capsid. The nucleic acid of herpes simplex virus type 1 and adenovirus type 3 is DNA, wherein the former has the envelope, and the latter does not have the envelope. By contrast, the nucleic acid of influenza virus type A and coxsackie virus group B type 1 is RNA, wherein the former has the envelope, and the latter does not have the envelope. National Institute of Health is the opinion that a substance of the antiviral ability against all the viruses of these types is highly possibly one of the antiviral ability against almost all the viruses including SRSV.
Taking these opinions into consideration, the present inventors have repeatedly investigated a substance of the antiviral ability against the above respective viruses, and thus the present invention has been consequently completed.
That is, the present invention resides in an antiviral agent comprising an active ingredient of a heat-treated calcium component-containing substance.
The calcium-containing substance expresses the antiviral ability if it is heat-treated.
Since the antiviral agent does not release any substance to damage health of animals and plants, fish and shellfish are neither dead nor sickened even if they are put in water containing the antiviral agent. In addition, since the fish and the shellfish take the water at the same time when they breathe, a dissolved ingredient of the antiviral agent in the water is also taken and kills the viruses in the fish and the shellfish. Thus, the antiviral agent of the present invention kills only the viruses easily and simply without killing and sickening the fish and the shellfish. Similarly, the antiviral agent can kill the viruses adhering to vegetables. The health of humans and animals is not damaged even if they take the animals and the plants whose viruses are sterilized by the antiviral agent.
Furthermore, the antiviral agent can prevent the bacterial food poisoning by killing the Salmonella, the Escherichia coli or the like as well as the viral food poisoning.
The calcium component-containing substance is preferably exemplified by at least one of a calcium carbonate-containing substance originating from an animal and a calcium carbonate-containing mineral. More specifically, it is possible to exemplify limestone and at least one selected from a group consisting of clamshell, eggshell, crustacean shell, bone, coral, and pearl.
The calcium carbonate-containing substance originating from the animal is originally waste. The calcium carbonate-containing mineral such as limestone is a natural product. Therefore, it is possible to furnish the raw material and is possible to provide the antiviral agent inexpensively.
Especially, when oyster shell is used as the clamshell, it is possible to obtain the fast-acting antiviral agent of an excellent antiviral activity. Therefore, it is preferable to use the oyster shell.
The preferable antiviral agent is powder having an average particle size of not more than 10 xcexcm. Such an average particle size increases the contact area of the antiviral agent with the virus, thereby further improving the antiviral ability.
The heat-treated calcium-containing substance has the antiviral ability against herpes simplex virus type 1, adenovirus type 3, influenza virus type A, coxsackie virus group B type 1 or the like which are representative viruses in classification, thereby decreasing the number of these viruses.
In another aspect, the present invention resides in a method of producing an antiviral agent, comprising a heat treatment step of heat-treating a calcium component-containing substance.
Accordingly, the calcium component-containing substance expresses the antiviral ability.
The calcium component-containing substance is preferably heat-treated such that the temperature is not less than 650xc2x0 C. and less than a melting point thereof. In this case, the sufficient heat treatment time is 2 to 13 hours.
The method preferably comprises, after the heat treatment step, a pulverizing step of pulverizing the heat-treated calcium component-containing substance so that an average particle size can be not more than 10 xcexcm since the contact area of the pulverized calcium-containing substance with the virus is increased. Therefore, it is possible to obtain the antiviral agent of the excellent antiviral ability.
The method preferably comprises, before the heat treatment step, a pre-pulverizing step of pulverizing the calcium component-containing substance so that an average particle size can be 100 xcexcm to 20 mm. By pre-pulverizing the calcium component-containing substance into a granular form, the heat treatment is enhanced in the heat treatment step in a short period of time uniformly from the surface to the inside of the granular calcium component-containing substance.
At least one of a calcium carbonate-containing substance originating from an animal and a calcium carbonate-containing mineral is preferably used as the calcium component-containing substance. More specifically, at least one selected from the group consisting of clamshell, eggshell, crustacean shell, bone, coral, and pearl is preferably used as the calcium carbonate-containing substance originating from the animal, and limestone is preferably used as the calcium carbonate-containing mineral. As described above, the calcium carbonate-containing substance originating from the animal is originally the waste. By contrast, the calcium carbonate-containing mineral such as limestone is the natural product. Therefore, it is possible to supply the raw material for the antiviral agent inexpensively.
Before the heat treatment step, it is preferable to provide a washing step of washing the calcium carbonate component-containing substance originating from the animal which is used as the calcium component-containing substance. Accordingly, it is possible to prevent malodor in the heat treatment step and damage of a heat treatment apparatus from being generated.
When clamshell, which has been left to stand for the elapse of time of not less than two years after removing a living body of clam therefrom, is used as the calcium carbonate-containing substance originating from the animal, the malodor is not generated and the heat treatment apparatus is not damaged, even if the heat treatment step is performed without the washing treatment. In other words, the washing treatment is not necessary. Therefore, the production efficiency of the antiviral agent is improved.
The above and other objects, features, and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings in which a preferred embodiment of the present invention is shown by way of illustrative example.